A common type of toilet flush valve member includes a float device with a float and seal, lying at the outer end of a yoke or frame, with the inner end of the frame pivotally mounted about a horizontal axis. When a chain initially pulls the float up to start a flushing, the buoyancy of the float keeps the flush valve member raised until almost all water has exited the tank. Then the flush valve member pivots down and its seal seals against a valve seat while the tank is refilled with water. Most toilets in present use, dispense about three gallons of water in each flushing. Municipalities wish to reduce the amount of waste water that passes through drain pipes and that must be treated before discharge. This can be accomplished by reducing the amount of water dispensed in each flushing.
One approach to reducing water usage, includes providing a second hole in the float, in addition to the drain hole at the bottom of the float. When the flush valve pivots up during a flushing, the second hole allows air to escape from the float chamber while water flows into the float chamber. This progressively decreases the buoyancy of the float, until it becomes heavy enough and closes the flush valve when perhaps only two gallons instead of three have been dispensed.
When setting up the new flush member, it is desirable to be able to adjust, in small increments, the amount of water dispensed in each flushing. This can be accomplished by allowing the float to be turned about a vertical axis, so the vertical height between the air escape hole and the usual water drain hole in a raised flush member can be varied. U.S. Pat. No. 4,419,773 by Sullivan describes an adjustable flush valve member of this type, wherein the frame is provided with a large diameter flange at its periphery, that lies in a horizontal plane (when the valve is lowered). The float device is provided with a groove at its periphery that includes walls lying below and above the flange to enable the float to turn about the flange. Also, the walls of the groove include teeth that are engaged by a detent on the frame to hold the float at any rotational position to which it is turned. While this approach enables fine adjustment of the float rotational position, it can result in difficult mounting of the float device on the frame, rigidizing of the float device seal and possible leakage, and difficult turning of the float device. The enlarged diameter of the rotation joint where the float device is rotatably coupled to the frame, results in high friction against float rotation and the possibility that there can be a "jamming" that makes it difficult to turn the float device. Turning of the float device can be especially difficult because it usually lies at the bottom of a wet tank. A flush valve member whose closing delay is adjustable by turning a float device, wherein float turning occurred with relatively low friction while the float was securely held in any of a plurality of rotational positions, and with the float device being easily mounted on the frame in a"loose" coupling that permitted float device tilt, would be of value.